Structured Logging - Observability Patterns

Consistent, machine-readable logging across the full stack. The backend uses structlog with JSON output; the frontend uses a custom Logger class. This skill codifies conventions for both and adds correlation IDs, log context, and level guidelines.

Description

Enforces JSON-structured logging with correlation IDs, consistent log levels, and contextual metadata across the FastAPI backend (structlog) and Next.js frontend (Logger class). Covers sensitive data redaction, request tracing, and observability best practices.

When to Apply

Positive Triggers

• Adding logging to new modules or API endpoints
• Reviewing existing log statements for consistency
• Implementing request tracing or correlation IDs
• Debugging production issues via log analysis
• Setting up log aggregation or monitoring pipelines
• User mentions: "logging", "logs", "observability", "tracing", "monitoring", "debug"